Core Description The Center will have 4 projects ? Project 1: Clinician Based Appropriateness ? Project 2: Outcomes Based Appropriateness ? Project 3: Patient Preferences Appropriateness ? Project 4 : Economic Based Appropriateness All the four Projects in the Center will utilize data collected in various ways from patients seen by a sample of practicing chiropractic providers in four national sites. The national sites will be selected during the first year of the project and will represent major regions of the country to enhance the generalizability of the findings to the United States overall. Within each ofthe four sites, we will identify and recruit a sample of 20 practicing chiropractors (i.e., 80 in total). If a chiropractor is interested in participating, we then will check to see if they meet the following eligibility requirements: (a) they typically see at least 5 patients a day who are being treated for chronic cervical pain; (b) they are willing to allow our team to recruit interview and shadow 10 patients through their visit over a 2-day period; (c) they will allow us to review and abstract 10 random patient charts and the 10 whom we interview; and (d) they will provide basic information about themselves and their practices. Each project has slightly different, but highly overlapping, data collection requirements, including: (a) the abstraction of patient files (Project 1); (b) face-to-face patient interviews (Project 1,2 4); (c) observations of treatment encounters (Project 3); (d); provider interviews (Projects 1,2,3,4); (e) questionnaires about each practice (Project 1, 3); and (f) patient follow-up telephone interviews (Projects 1, 2,3 4). Rather than have each project collect its own national data we have created one Data Collection and Management Core (DCMC) or the whole Center. This not only results in costs efficiencies but also ensures a much great level of integration of the projects and the data.